Stainless steel is used as a heat–resistant material not only in air, but also in carburizing atmospheres containing CO and CO2.
Carburization may cause austenization for ferritic stainless steels. In this study, the high–temperature oxidation behaviors of 17ÿ Cr ferritic
stainless steels with and without the addition of austenite–forming elements, such as Cu and Ni, in a carburizing atmosphere at 1123 K were
investigated. The steels did not exhibit breakaway oxidation in the temperature range of 1123–1273 K in air. However, doping the steels with
Cu and Ni enhanced breakaway oxidation in a carburizing atmosphere at 1123 K. Traces of austenization and carburization were observed at
the base metal under the breakaway oxidation scale of the 17ÿ Cr steel doped with 1ÿ Cu and 1ÿ Ni. Thus, it is proposed that the breakaway
oxidation of the ferritic stainless steels in a carburizing atmosphere is attributed to austenization induced by carburization and doping with
austenite–forming elements.